Negative pressure type head slider and disk drive

ABSTRACT

A disk drive including a negative pressure type head slider having a transducer for reading/writing data from/to a disk having a plurality of tracks, and an actuator for moving the head slider across the tracks of the disk. The actuator includes an actuator arm rotatably mounted on a base of the head slider, a suspension fixed at a base end portion thereof to a front end portion of the actuator arm, and the head slider mounted on a front end portion of the suspension. The head slider includes a front pad having a raised surface and a step surface lower in level than the raised surface, the transducer formed near the air outlet end, and a first groove for generating a negative pressure by expanding air once compressed at the front pad. The bottom surface of the first groove is formed with a plurality of second grooves continuously extending from the downstream side of the front pad to the air outlet end. The second grooves are spaced from each other in the transverse direction of the head slider.

This is a continuation of International PCT Application No.PCT/JP00/01529 filed Mar. 14, 2000 which was not published in English.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a magnetic disk drive, andmore particularly to a negative pressure type head slider for a magneticdisk drive.

2. Description of the Related Art

In recent magnetic disk drives with decreasing size and increasingstorage capacity, it has been desired to reduce the flying height of ahead slider and realize contact recording/reproduction such that thehead slider flies a microscopic height from a recording medium such as amagnetic disk or comes into contact with the recording medium. To reducethe flying height of the head slider, the surface roughness of thesurface of the magnetic disk must be reduced. In a contact start andstop (CSS) type magnetic disk drive heretofore widely used, a flyingsurface of a magnetic head slider comes into contact with a magneticdisk upon stoppage of rotation of the magnetic disk, and flies above thesurface of the magnetic disk during rotation of the magnetic disk by theaction of an air flow produced in concert with the rotation of themagnetic disk.

In the CSS type magnetic disk drive, high flying stability andmicroscopic flying height (on the order of submicrons) can be ensured.However, the air bearing surface (flying surface) of the head slidercomes into contact with the magnetic disk upon stoppage of rotation ofthe magnetic disk, and slides relative to the magnetic disk at startingand stopping the disk drive. To cope with this, a protective film formedof a hard material such as carbon and a lubricating layer for reducingthe friction and wearing of the protective film to improve thedurability of the magnetic disk are formed on a recording layer of themagnetic disk. Although the friction and wearing of the protective filmcan be reduced by the presence of the lubricating layer, there is apossibility of stiction between the magnetic disk and the head slider inthe rest condition of the magnetic disk, causing a problem that the diskdrive cannot be started.

With a recent increase in amount of information, the recording densityor storage capacity of the magnetic disk drive is remarkably increasingand the size of the magnetic disk drive is remarkably decreasing. Thesize reduction of the magnetic disk drive is accompanied by a decreasein torque of a spindle motor in the disk drive, and the disk surface ofthe magnetic disk is smoothened for the increasing recording density.Due to these factors, much attention is now focused on the stictionproblem causing a defective operation. As measures against this stictionproblem, it has been proposed to apply texture forming by laser to a CSSzone of the magnetic disk or provide a plurality of projections on theflying surface (air bearing surface) of the head slider, therebyreducing a contact area between the head slider and the disk surface.

A negative pressure type magnetic head slider is widely used in recentmagnetic disk drives, so as to reduce the flying height of the magnetichead slider from the magnetic disk. Such a negative pressure typemagnetic head slider has a groove for generating a negative pressure byexpanding air once compressed near an air inlet end of the head slider.In the magnetic disk drive using the negative pressure type magnetichead slider, there is a possibility that dust or dirt may be depositedon the bottom surface of the groove of the head slider in the CSSoperation or seek operation, and when the amount of dust or dirtdeposited exceeds a permissible amount, it may fall onto the disksurface to cause head crash.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a diskdrive which can suppress the deposition of dust or dirt possiblyexisting inside the disk drive onto the bottom surface of the groove ofa negative pressure type head slider, thereby effectively preventinghead crash due to falling of the dust or dirt onto the disk surface.

In accordance with an aspect of the present invention, there is provideda disk drive comprising a housing having a base; a disk rotatablymounted in the housing and having a plurality of tracks; a negativepressure type head slider having a transducer for reading/writing datafrom/to the disk, a disk opposing surface, an air inlet end, and an airoutlet end; and an actuator for moving the head slider across the tracksof the disk; the actuator comprising an actuator arm rotatably mountedon the base; a suspension fixed at a base end portion thereof to a frontend portion of the actuator arm; and the head slider mounted on a frontend portion of the suspension; the head slider comprising a front padformed on the disk opposing surface at a position near the air inletend, the front pad having a raised surface and a step surface lower inlevel than the raised surface; the transducer formed near the air outletend; a first groove for generating a negative pressure by expanding aironce compressed at the front pad; and a plurality of second groovesformed on the bottom surface of the first groove so as to continuouslyextend from the downstream side of the front pad to the air outlet end,the second grooves being spaced from each other in the transversedirection of the head slider.

Preferably, the second grooves extend along air streamlines in the CSSzone. As a modification, the second grooves may extend substantiallyparallel to an air inlet direction in the CSS zone. As anothermodification, the angle of extension of the second grooves with respectto the longitudinal direction of the head slider may be continuouslychanged so that the direction of extension of the innermost secondgroove is substantially parallel to an air inlet direction in theinnermost track condition and the direction of extension of theoutermost second groove is substantially parallel to an air inletdirection in the outermost track condition.

In accordance with another aspect of the present invention, there isprovided a disk drive comprising a housing having a base; a diskrotatably mounted in the housing and having a plurality of tracks; anegative pressure type head slider having a transducer forreading/writing data from/to the disk, a disk opposing surface, an airinlet end, and an air outlet end; and an actuator for moving the headslider across the tracks of the disk; the actuator comprising anactuator arm rotatably mounted on the base; a suspension fixed at a baseend portion thereof to a front end portion of the actuator arm; and thehead slider mounted on a front end portion of the suspension; the headslider comprising a front pad formed on the disk opposing surface at aposition near the air inlet end, the front pad having a raised surfaceand a step surface lower in level than the raised surface; thetransducer formed near the air outlet end; a groove for generating anegative pressure by expanding air once compressed at the front pad; anda plurality of rails formed on the bottom surface of the groove so as tocontinuously extend from the downstream side of the front pad to the airoutlet end, the rails being spaced from each other in the transversedirection of the head slider.

In accordance with a further aspect of the present invention, there isprovided a disk drive comprising a housing having a base; a diskrotatably mounted in the housing and having a plurality of tracks; anegative pressure type head slider having a transducer forreading/writing data from/to the disk, a disk opposing surface, an airinlet end, and an air outlet end; and an actuator for moving the headslider across the tracks of the disk; the actuator comprising anactuator arm rotatably mounted on the base; a suspension fixed at a baseend portion thereof to a front end portion of the actuator arm; and thehead slider mounted on a front end portion of the suspension; the headslider comprising a pair of rails formed on the disk opposing surface,each of the rails having a flat air bearing surface for generating aflying force during rotation of the disk; the transducer formed near theair outlet end at a position where one of the rails is formed; a firstgroove defined between the rails for generating a negative pressure byexpanding air once compressed near the air inlet end; and a plurality ofsecond grooves formed on the bottom surface of the first groove so as tocontinuously extend from near the air inlet end to the air outlet end,the second grooves being spaced from each other in the transversedirection of the head slider.

In accordance with a still further aspect of the present invention,there is provided a disk drive comprising a housing having a base; adisk rotatably mounted in the housing and having a plurality of tracks;a negative pressure type head slider having a transducer forreading/writing data from/to the disk, a disk opposing surface, an airinlet end, and an air outlet end; and an actuator for moving the headslider across the tracks of the disk; the actuator comprising anactuator arm rotatably mounted on the base; a suspension fixed at a baseend portion thereof to a front end portion of the actuator arm; and thehead slider mounted on a front end portion of the suspension; the headslider comprising a pair of first rails formed on the disk opposingsurface, each of the first rails having a flat air bearing surface forgenerating a flying force during rotation of the disk; the transducerformed near the air outlet end at a position where one of the firstrails is formed; a groove defined between the first rails for generatinga negative pressure by expanding air once compressed near the air inletend; and a plurality of second rails formed on the bottom surface of thegroove so as to continuously extend from near the air inlet end to theair outlet end, the rails being spaced from each other in the transversedirection of the head slider.

The above and other objects, features and advantages of the presentinvention and the manner of realizing them will become more apparent,and the invention itself will best be understood from a study of thefollowing description and appended claims with reference to the attacheddrawings showing some preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a magnetic disk drive with a coverremoved;

FIG. 2A is a perspective view of a head assembly;

FIG. 2B is a longitudinal sectional view of the head assembly;

FIG. 3 is an exploded perspective view of the head assembly;

FIG. 4 is a plan view of a negative pressure type head slider accordingto a first preferred embodiment of the present invention;

FIG. 5 is a partially cutaway perspective view of the head slider shownin FIG. 4;

FIG. 6 is a partially cutaway perspective view of a negative pressuretype head slider according to a second preferred embodiment of thepresent invention;

FIG. 7 is a plan view of a negative pressure type head slider accordingto a third preferred embodiment of the present invention;

FIG. 8 is a plan view of a negative pressure type head slider accordingto a fourth preferred embodiment of the present invention;

FIG. 9 is a cross section taken along the line 9—9 in FIG. 8;

FIG. 10 is a plan view of a negative pressure type head slider accordingto a fifth preferred embodiment of the present invention;

FIG. 11 is a partially cutaway perspective view of the head slider shownin FIG. 10;

FIG. 12 is a partially cutaway perspective view of a negative pressuretype head slider according to a sixth preferred embodiment of thepresent invention;

FIG. 13 is a plan view of a negative pressure type head slider accordingto a seventh preferred embodiment of the present invention;

FIG. 14 is a plan view of a negative pressure type head slider accordingto an eighth preferred embodiment of the present invention;

FIG. 15 is a cross section taken along the line 15—15 in FIG. 14;

FIGS. 16A to 16I are schematic views showing a manufacturing method forthe head slider according to the first preferred embodiment;

FIGS. 17A to 17F are schematic views showing another manufacturingmethod for the head slider according to the first preferred embodiment;

FIGS. 18A to 18I are schematic views showing a manufacturing method forthe head slider according to the second preferred embodiment; and

FIGS. 19A to 19F are schematic views showing another manufacturingmethod for the head slider according to the second preferred embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Some preferred embodiments of the present invention will now bedescribed with reference to the drawings. Throughout the drawings,substantially the same parts are denoted by the same reference numerals.Referring to FIG. 1, there is shown a perspective view of a magneticdisk drive according to a first preferred embodiment of the presentinvention in the condition where a cover is removed. A shaft 4 is fixedto a base 2, and a spindle hub (not shown) is rotatably mounted on theshaft 4. The spindle hub is driven by a DC motor (not shown) to rotateabout the shaft 4. A plurality of magnetic disks 6 and spacers (notshown) are mounted on the spindle hub so as to be alternately stacked.That is, the plural magnetic disks 6 are fixedly mounted on the spindlehub by securing a disk clamp 8 to the spindle hub by means of aplurality of screws 10, and are equally spaced a given distance by thespacers.

Reference numeral 12 denotes a rotary actuator consisting of an actuatorarm assembly 14 and a magnetic circuit 16. The actuator arm assembly 14is rotatable about a shaft 18 fixed to the base 2. The actuator armassembly 14 includes an actuator block 20 rotatably mounted on the shaft18 through a pair of bearings (not shown), a plurality of actuator arms22 extending horizontally from the actuator block 20 in one direction,and a head assembly 24 fixed to a front end portion of each actuator arm22.

Each head assembly 24 includes a negative pressure type head slider 26having an electromagnetic transducer (magnetic head element) forreading/writing data from/to the corresponding magnetic disk 6, and aload beam (suspension) 28 having a front end portion supporting the headslider 26 and a base end portion fixed to the corresponding actuator arm22. A coil (not shown) is supported on the opposite side of the actuatorarms 22 with respect to the shaft 18. The coil is inserted in a gap ofthe magnetic circuit 16. The magnetic circuit 16 and the coil constitutea voice coil motor (VCM) 30. Reference numeral 32 denotes a flexibleprinted circuit board (FPC) for supplying a write signal to theelectromagnetic transducer and for taking a read signal from theelectromagnetic transducer. One end of the flexible printed circuitboard 32 is fixed to a side surface of the actuator block 20.

FIG. 2A is a perspective view of the head assembly 24, FIG. 2B is alongitudinal sectional view of the head assembly 24, and FIG. 3 is anexploded perspective view of the head assembly 24. As best shown in FIG.3, the load beam 28 is integrally formed with a gimbal 34. The gimbal 34is defined by forming a U-shaped slit 36 at a front end portion of theload beam 28. The load beam 28 is formed of stainless steel, and it hasa thickness of about 22 μm. The load beam 28 includes a spring portion28 a for pressing the head slider 26 on the corresponding disk 6 and arigid portion 28 b. A reinforcing plate 38 is fixed to the back surfaceof the rigid portion 28 b by spot welding or the like.

The reinforcing plate 38 is formed of stainless steel, for example, andit has a thickness about 1.0 times to about 2.0 times, preferably, about1.3 times to about 1.5 times the thickness of the load beam 28. Bysetting the thickness of the reinforcing plate 38 in the above-mentionedrange, the resonance frequency of the head assembly 24 can be increasedand its mass increase can be minimized. If the thickness of thereinforcing plate 38 is set less than a value 1 times the thickness ofthe load beam 28, the rigidity of the rigid portion 28 b decreases tocause a reduction in the resonance point. Conversely, if the thicknessof the reinforcing plate 38 is set greater than a value 2 times thethickness of the load beam 28, the mass of the head assembly 24 isincreased to cause a reduction in impact acceleration upon separation ofthe head slider 26 from the disk 6, causing a deterioration in shockresistance.

While the load beam 28 is a platelike member, the spring portion 28 a isbent round so as to press the head slider 26 on the corresponding disk 6in actual use. The reinforcing plate 38 is formed at its front endportion with a pivot 40 having a tip kept in contact with the backsurface of the gimbal 34 to support the head slider 26. Further, aspacer 42 formed of aluminum is fixed by spot welding to a base endportion of the load beam 28.

In the head assembly 24, the gimbal 34 is set so that the flexuralrigidity of a front portion of the gimbal 34 with respect to the pivot40 is equal to that of a rear portion of the gimbal 34. Accordingly,although the gimbal 34 is pushed from its back side by the pivot 40, thehead slider 26 is not tilted. As a result, the head slider 26 can beloaded without applying a moment, thereby realizing a stable flyingattitude of the head slider 26. Further, since the head slider 26 ispreloaded by the pivot 40, the friction at the pivot 40 upon loading onthe head slider 26 becomes large by the preload, so that the limit tothe slip at the pivot 40 can be maintained to be high even when thebiasing force of the spring portion 28 a for pressing the head slider 26on the disk 6 is small.

Referring to FIG. 4, there is shown a plan view of the negative pressuretype head slider 26 according to the first preferred embodiment of thepresent invention. FIG. 5 is a partially cutaway perspective view of thehead slider 26 shown in FIG. 4. The head slider 26 is in the form ofrectangular parallelepiped, and has an air inlet end 26 a and an airoutlet end 26 b. The upper surface of the head slider 26 as viewed inFIGS. 4 and 5 is a disk opposing surface adapted to face thecorresponding disk 6. A front pad 44 is formed on the disk opposingsurface of the head slider 26 at a position adjacent to the air inletend 26 a, and a pair of rear pads 46 and 48 are formed on the diskopposing surface of the head slider 26 at positions adjacent to the airoutlet end 26 b and transversely spaced from each other. The front pad44 is formed with a raised surface (air bearing surface) 50 extending inthe transverse direction of the head slider 26 and a step surface 52lower in level than the raised surface 50.

Similarly, the rear pads 46 and 48 are formed with raised surfaces (airbearing surfaces) 54 and 56 and step surfaces 58 and 60 lower in levelthan the raised surfaces 54 and 56, respectively. The raised surface 54is smaller in area than the raised surface 56. Accordingly, a flyingforce applied to the raised surface 56 is larger than that applied tothe raised surface 54 in the head slider 26. An electromagnetictransducer 62 is formed near the air outlet end of the rear pad 46, andthe distance between the head slider 26 and the disk surface duringrotation of the disk 6 is minimum near the electromagnetic transducer62.

When the disk 6 is rotated to generate an air flow along the disksurface, the air flow acts on the raised surfaces 50, 54, and 56. As aresult, flying forces for flying the head slider 26 above the disksurface are generated on the raised surfaces 50, 54, and 56. In the headslider 26, the area of the raised surface 50 is relatively large, sothat a relatively large flying force is generated on the raised surface50 during rotation of the disk 6. As a result, the head slider 26 ismaintained in an inclined attitude at a pitch angle a such that the airinlet end 26 a is tilted up.

A pair of projections 64 and 66 for preventing the stiction of the headslider 26 upon CSS are formed on the step surface 52 of the front pad44. Similarly, a projection 68 is formed on the step surface 60 of therear pad 48. A pair of side pads 70 and 72 extend from the transverseends of the front pad 44 toward the rear pads 46 and 48, respectively.The side pad 70 is also formed with a projection 74 for prevention ofthe stiction.

A first groove 76 for generating a negative pressure is defined betweenthe side pads 70 and 72 on the downstream side of the front pad 44. Thefirst groove 76 extends from a position upstream of the longitudinalcenter of the head slider 26 to the air outlet end 26 b. Accordingly,when passing the raised surface 50 of the front pad 44, the air flow isexpanded in the first groove 76 in a direction perpendicular to the disksurface, thereby generating a negative pressure in the first groove 76.This negative pressure comes into balance with the above-mentionedflying forces applied to the raised surfaces 50, 54, and 56, therebydefining a flying height of the head slider 26.

A plurality of narrow second grooves 78 are formed on the bottom surfaceof the first groove 76 so as to continuously extend from the downstreamside of the front pad 44 to the air outlet end 26 b. The second grooves78 are spaced from each other in the transverse direction of the headslider 26. The second grooves 78 extend along different streamlines 79of air generated on the bottom surface of the first groove 76.Preferably, the second grooves 78 extend along such air streamlinesgenerated on the bottom surface of the first groove 76 in the CSS zone.By forming these narrow grooves 78 on the bottom surface of the firstgroove 76, dust or dirt deposited on the bottom surface of the firstgroove 76 during the entry of air into the first groove 76 can be guidedalong the second grooves 78 to the air outlet end 26 b, therebysuppressing the accumulation of the dust or dirt on the bottom surfaceof the first groove 76. Accordingly, the dust or dirt deposited on thebottom surface of the first groove 76 can be prevented from falling downonto the disk 6, thereby preventing head crash due to the dust or dirt.Preferably, each second groove 78 has a depth of 2 μm or less and awidth of 10 to 20 μm.

Further, a porous polymer layer of polyurethane or the like may bebonded to the air outlet end 26 b, so as to absorb the dust or dirtguided to the air outlet end 26 b and thereby prevent scattering of thedust or dirt into the internal space of the disk drive. Preferably,water-repellent treatment is applied to each second groove 78. Forexample, this water-repellent treatment may be effected by mixing afluorine-containing gas such as CF₄ into an etching gas mainlycontaining Ar in forming the second grooves 78 by ion beam etching.

Referring to FIG. 6, there is shown a partially cutaway perspective viewof a negative pressure type head slider 26A according to a secondpreferred embodiment of the present invention. The head slider 26Aaccording to the second preferred embodiment has a plurality of rails 80in place of the second grooves 78 formed in the first groove 76 of thehead slider 26 according to the first preferred embodiment. The otherconfiguration of the second preferred embodiment is similar to that ofthe first preferred embodiment. Preferably, each rail 80 has a height of0.4 μm or less and a width of 10 to 20 μm.

The plural rails 80 are formed along the air streamlines generated onthe bottom surface of the groove 76 in the CSS zone. The plural rails 80extend continuously from the downstream side of the front pad 44 to theair outlet end 26 b, and they are spaced from each other in thetransverse direction of the head slider 26A. With this configuration,dust or dirt deposited on the bottom surface of the groove 76 during theentry of air into the groove 76 can be guided along the rails 80 to theair outlet end 26 b, thereby preventing the accumulation of the dust ordirt on the bottom surface of the groove 76.

Referring to FIG. 7, there is shown a plan view of a negative pressuretype head slider 26B according to a third preferred embodiment of thepresent invention. The head slider 26B according to the third preferredembodiment has a plurality of second grooves 82 extending in a directionsubstantially parallel to an air inlet direction shown by arrow 84 inthe CSS zone. The second grooves 82 are formed on the bottom surface ofthe first groove 76. In the CSS zone, the head slider 26B comes intocontact with the disk 6, and dust or dirt is therefore prone to depositon the bottom surface of the groove 76. In consideration of this fact,the second grooves 82 are formed on the bottom surface of the firstgroove 76 so as to extend in a direction substantially parallel to theair inlet direction 84 in the CSS zone, so that the dust or dirtdeposited on the bottom surface of the first groove 76 in the CSS zonecan be positively guided along the second grooves 82 to the air outletend 26 b. The other configuration of this preferred embodiment issimilar to that of the first preferred embodiment. In modification, aplurality of rails as shown in FIG. 6 may be formed in place of theplural second grooves 82.

Referring to FIG. 8, there is shown a plan view of a negative pressuretype head slider 26C according to a fourth preferred embodiment of thepresent invention. FIG. 9 is a cross section taken along the line 9—9 inFIG. 8. The head slider 26C according to the fourth preferred embodimenthas a plurality of second grooves 86 extending in different directionsin the first groove 76. That is, the angle of extension of the secondgrooves 86 with respect to the longitudinal direction of the head slider26C is continuously changed in such a manner that the direction ofextension of the innermost groove 86 is substantially parallel to an airinlet direction shown by arrow 88 in the innermost track condition andthe direction of extension of the outermost groove 86 is substantiallyparallel to an air inlet direction shown by arrow 90 in the outermosttrack condition. Furthermore, as shown in FIG. 9, the depth of eachsecond groove 86 is continuously decreased from the air inlet side tothe air outlet end 26 b. Alternatively, the depth of each second groove86 may be stepwise decreased toward the air outlet end 26 b.

Thus, the angle of extension of the second grooves 86 is continuouslychanged in this preferred embodiment, so that any one of the grooves 86becomes substantially parallel to any air inlet direction over the seekrange of the head slider 26C. Accordingly, dust or dirt deposited on thebottom surface of the groove 76 can be effectively guided along thegroove 86 to the air outlet end 26 b. Further, the reason why the depthof each second groove 86 is set largest at its upstream end is that thenegative pressure generated in the groove 76 is largest at a positionjust downstream of the front pad 44 and it is therefore expected thatthe deposition of dust or dirt becomes maximum at this position.Accordingly, by setting the depth of each second groove 86 as mentionedabove, the dust or dirt deposited can be positively removed. Also in thefirst and third preferred embodiments, the depths of the second grooves78 and 82 may be changed as in the head slider 26C according to thefourth preferred embodiment shown in FIG. 9.

Referring to FIG. 10, there is shown a plan view of a negative pressuretype head slider 26D according to a fifth preferred embodiment of thepresent invention. FIG. 11 is a partially cutaway perspective view ofthe head slider 26D shown in FIG. 10. The head slider 26D has an airinlet end 26 a and an air outlet end 26 b. The upper surface of the headslider 26D as viewed in FIGS. 10 and 11 is a disk opposing surfaceadapted to face the corresponding disk 6. A pair of rails 92 and 94 forgenerating a positive pressure are formed on the disk opposing surfaceof the head slider 26D. The rails 92 and 94 have flat air bearingsurfaces 92 a and 94 a for generating a flying force during rotation ofthe disk 6, respectively.

The rails 92 and 94 are formed with tapering surfaces 92 b and 94 badjacent to the air inlet end 26 a, respectively. A center rail 104 isformed between the rails 92 and 94 near the air inlet end 26 a. Thecenter rail 104 also has a tapering surface 104 b adjacent to the airinlet end 26 a. A slit 106 is defined between the rail 92 and the centerrail 104, and a slit 108 is defined between the rail 94 and the centerrail 104. A first groove 110 for generating a negative pressure byexpanding the air once compressed near the air inlet end 26 a is definedbetween the rails 92 and 94 on the downstream side of the center rail104. An electromagnetic transducer 62 is formed near the air outlet endof the rail 92. The rail 92 has a relatively large width near the airinlet end and near the air outlet end and has a relatively small widthat an intermediate portion therebetween. Similarly, the rail 94 has arelatively large width near the air inlet end and near the air outletend and has a relatively small width at an intermediate portiontherebetween. By setting the widths of the rails 92 and 94 as mentionedabove, fluctuations in flying attitude of the head slider 26D due tochanges in yaw angle can be suppressed.

A pair of projections 96 and 98 for preventing the stiction of the headslider 26D upon CSS are formed on the rail 92. Similarly, a pair ofprojections 100 and 102 for prevention of the stiction are formed on therail 94. Further, a plurality of narrow second grooves 112 are formed onthe bottom surface of the first groove 110 so as to continuously extendfrom the air inlet side to the air outlet end 26 b. The second grooves112 are spaced from each other in the transverse direction of the headslider 26D. The second grooves 112 extend along different streamlines113 of air generated on the bottom surface of the first groove 110.Preferably, the second grooves 112 extend along such air streamlinesgenerated on the bottom surface of the first groove 110 in the CSS zone.

By forming these narrow grooves 112 on the bottom surface of the firstgroove 110, dust or dirt deposited on the bottom surface of the firstgroove 110 during the entry of air into the first groove 110 can beguided along the second grooves 112 to the air outlet end 26 b, therebysuppressing the accumulation of the dust or dirt on the bottom surfaceof the first groove 110.

Referring to FIG. 12, there is shown a partially cutaway perspectiveview of a negative pressure type head slider 26E according to a sixthpreferred embodiment of the present invention. The head slider 26Eaccording to the sixth preferred embodiment has a plurality of rails 114in place of the second grooves 112 in the fifth preferred embodimentshown in FIGS. 10 and 11. The other configuration of the sixth preferredembodiment is similar to that of the fifth preferred embodiment shown inFIGS. 10 and 11. According to the sixth preferred embodiment, dust ordirt deposited on the bottom surface of the groove 110 during the entryof air into the groove 110 can be guided along the rails 114 to the airoutlet end 26 b, thereby preventing the accumulation of the dust or dirton the bottom surface of the groove 110.

Referring to FIG. 13, there is shown a plan view of a negative pressuretype head slider 26F according to a seventh preferred embodiment of thepresent invention. The head slider 26F according to the seventhpreferred embodiment has a plurality of second grooves 116 extending ina direction substantially parallel to an air inlet direction shown byarrow 18 in the CSS zone. The second grooves 116 are formed on thebottom surface of the first groove 110. Like the head slider 26Baccording to the third preferred embodiment shown in FIG. 7, the headslider 26F has a great effect of removing the dust or dirt especially inthe CSS zone. The other configuration of this preferred embodiment issimilar to that of the fifth preferred embodiment shown in FIGS. 10 and11.

Referring to FIG. 14, there is shown a plan view of a negative pressuretype head slider 26G according to an eighth preferred embodiment of thepresent invention. FIG. 5 is a cross section taken along the line 15—15in FIG. 14. The head slider 26G according to the eighth preferredembodiment has a plurality of second grooves 120 extending in differentdirections in the first groove 110. That is, the angle of extension ofthe second grooves 120 with respect to the longitudinal direction of thehead slider 26G is continuously changed in such a manner that thedirection of extension of the innermost groove 120 is substantiallyparallel to an air inlet direction shown by arrow 122 in the innermosttrack condition and the direction of extension of the outermost groove120 is substantially parallel to an air inlet direction shown by arrow124 in the outermost track condition. Furthermore, as shown in FIG. 15,the depth of each second groove 120 is continuously decreased from theair inlet side to the air outlet end 26 b. Alternatively, the depth ofeach second groove 120 may be stepwise decreased toward the air inletend 26 b. Further, also in the fifth and seventh preferred embodiments,the depths of the second grooves 112 and 116 may be continuously orstepwise decreased from the air inlet side to the air outlet end 26 b.

A manufacturing method for the head slider 26 according to the firstpreferred embodiment will now be described with reference to FIGS. 16Ato 16I. This manufacturing method is a method to which a second grooveforming process is added after conventional processes. As shown in FIG.16A, a photoresist 132 is first applied to the upper surface of a slidersubstrate 130 at a position where the air bearing surface is to beformed. As shown in FIG. 16B, the upper surface of the slider substrate130 is next etched by the difference in level between the air bearingsurface (raised surface) and the step surface by ion beam etching mainlyusing Ar gas. Further, the photoresist 132 is next removed (FIG. 16C).In this condition, the air bearing surface 134 is formed.

As shown in FIG. 16D, a photoresist 136 is next applied to the airbearing surface 134 and the upper surface of the slider substrate 130 ata position where the step surface is to be formed. As shown in FIG. 16E,the upper surface of the slider substrate 130 is next etched by apredetermined thickness by ion beam etching. Further, the photoresist136 is next removed (FIG. 16F). In this condition, the step surface 138and the first groove 140 are formed.

As shown in FIG. 16G, a photoresist 144 is next applied to the airbearing surface 134, the step surface 138, and the upper surface of theslider substrate 130 except a position 142 where the second grooves areto be formed. As shown in FIG. 16H, the upper surface of the slidersubstrate 130 is next etched by a predetermined thickness by ion beametching. Further, the photoresist 144 is next removed (FIG. 16I). Thus,the second grooves 146 (one of which being shown) are formed.

Referring to FIGS. 17A to 17F, there is shown another manufacturingmethod for the head slider 26. In this method, the step surface and thesecond grooves are simultaneously formed. As shown in FIG. 17A, aphotoresist 152 is first applied to the upper surface of the slidersubstrate 130 except a position 148 where the step surface is to beformed and a position 150 where the second grooves are to be formed. Asshown in FIG. 17B, the upper surface of the slider substrate 130 is nextetched by a predetermined thickness by ion beam etching. Further, thephotoresist 152 is next removed (FIG. 17C). In this condition, the airbearing surface 154 is formed.

As shown in FIG. 17D, a photoresist 156 is next applied to the airbearing surface 154 and the upper surface of the slider substrate 130 atthe position where the step surface is to be formed. As shown in FIG.17E, the upper surface of the slider substrate 130 is next etched by apredetermined thickness by ion beam etching. Further, the photoresist156 is next removed (FIG. 17F). Thus, the step surface 158, the firstgroove 160, and the second grooves 162 (one of which being shown) areformed. According to this method, the manufacturing process can beshortened by three steps as compared with the manufacturing method shownin FIGS. 16A to 16I.

A manufacturing method for the head slider 26A according to the secondpreferred embodiment shown in FIG. 6 will now be described withreference to FIGS. 18A to 18I. As shown in FIG. 18A, a photoresist 164is first applied to the upper surface of the slider substrate 130 at aposition where the air bearing surface (raised surface) is to be formed.As shown in FIG. 18B, the upper surface of the slider substrate 130 isnext etched by a predetermined thickness by ion beam etching. Further,the photoresist 164 is next removed (FIG. 18C). In this condition, theair bearing surface 166 is formed.

As shown in FIG. 18D, a photoresist 168 is next applied to the airbearing surface 166 and the upper surface of the slider substrate 130 ata position where the step surface is to be formed. As shown in FIG. 18E,the upper surface of the slider substrate 130 is next etched by apredetermined thickness by ion beam etching. Further, the photoresist168 is next removed (FIG. 18F). In this condition, the step surface 170is formed.

As shown in FIG. 18G, a photoresist 174 is next applied to the airbearing surface 166, the step surface 170, and the upper surface of theslider substrate 130 at a position where the rails are to be formed. Asshown in FIG. 18H, the upper surface of the slider substrate 130 is nextetched by a predetermined thickness by ion beam etching. Further, thephotoresist 174 is next removed (FIG. 18I). Thus, the groove 172 and therails 176 (one of which being shown) are formed.

Another manufacturing method for the head slider 26A according to thesecond preferred embodiment will now be described with reference toFIGS. 19A to 19F. In this method, the step surface and the rails aresimultaneously formed. As shown in FIG. 19A, a photoresist 178 is firstapplied to the upper surface of the slider substrate 130 at positionswhere the air bearing surface and the rails are to be formed. As shownin FIG. 19B, the upper surface of the slider substrate 130 is nextetched by a predetermined thickness by ion beam etching. Further, thephotoresist 178 is next removed (FIG. 19C). In this condition, the airbearing surface 180 is formed.

As shown in FIG. 19D, a photoresist 182 is next applied to the airbearing surface 180 and the upper surface of the slider substrate 130 ata position where the step surface is to be formed. As shown in FIG. 19E,the upper surface of the slider substrate 130 is next etched by apredetermined thickness by ion beam etching. Further, the photoresist182 is next removed (FIG. 19F). Thus, the step surface 184, the groove186, and the rails 188 (one of which being shown) are formed. Accordingto this method, the manufacturing process can be shortened by threesteps as compared with the manufacturing method shown in FIGS. 18A to18I.

In the negative pressure type head slider according to the presentinvention, the plural narrow grooves or rails are formed on the bottomsurface of the groove for generating a negative pressure. These narrowgrooves or rails extend along the air streamlines in the CSS zone orsubstantially parallel to an air inlet direction in the CSS zone.Alternatively, the angle of extension of these narrow grooves or railswith respect to the longitudinal direction of the head slider may becontinuously changed so that the direction of extension of the innermostgroove is substantially parallel to an air inlet direction in theinnermost track condition and the direction of extension of theoutermost groove is substantially parallel to an air inlet direction inthe outermost track condition.

By the formation of the plural narrow grooves or rails on the bottomsurface of the groove for generating a negative pressure, dust or dirtdeposited on the bottom surface of the negative pressure generatinggroove during the entry of air into this groove can be guided alongthese narrow grooves or rails to an air outlet end to thereby preventthe accumulation of the dust or dirt on the bottom surface of thenegative pressure generating groove. As a result, the dust or dirtdeposited on the bottom surface of the negative pressure generatinggroove can be prevented from falling down onto the disk, therebypreventing head crash due to the dust or dirt.

1. A disk drive comprising: a housing having a base; a disk rotatably mounted in said housing and having a plurality of tracks; a negative pressure type head slider having a transducer for reading/writing data from/to said disk, a disk opposing surface, an air inlet end, and an air outlet end; and an actuator for moving said head slider across said tracks of said disk; said actuator comprising: an actuator arm rotatably mounted on said base; a suspension fixed at a base end portion thereof to a front end portion of said actuator arm; and said head slider mounted on a front end portion of said suspension; said head slider comprising: a front pad formed on said disk opposing surface at a position near said air inlet end, said front pad having a raised surface and a step surface lower in level than said raised surface; said transducer formed near said air outlet end; a first groove for generating a negative pressure by expanding air once compressed at said front pad; and a plurality of second grooves formed on the bottom surface of said first groove so as to continuously extend from the downstream side of said front pad to said air outlet end, said second grooves being spaced from each other in the transverse direction of said head slider, said second grooves extending along air streamlines generated on the bottom surface of said first groove in a CSS zone.
 2. A disk drive according to claim 1, wherein said second grooves are treated with water-repellent.
 3. A negative pressure type head slider having a disk opposing surface, an air inlet end, and an air outlet end, comprising: a front pad formed on said disk opposing surface at a position near said air inlet end, said front pad having a raised surface and a step surface lower in level than said raised surface; a transducer formed near said air outlet end; a first groove for generating a negative pressure by expanding air once compressed at said front pad; and a plurality of second grooves formed on the bottom surface of said first groove so as to continuously extend from the downstream side of said front pad to said air outlet end, said second grooves being spaced from each other in the transverse direction of said head slider, said second grooves extending along air streamlines generated on the bottom surface of said first groove in a CSS zone.
 4. A negative pressure type head slider according to claim 3, wherein said second grooves are treated with water repellent.
 5. A negative pressure type head slider having a disk opposing surface, an air inlet end, and an air outlet end, comprising: a plurality of rails formed on said disk opposing surface, each of said rails having a flat air bearing surface for generating a flying force during rotation of said disk; a transducer formed near said air outlet end at a position where one of said rails is formed; a negative pressure generating surface defined between said plurality of rails; and a plurality of grooves formed in said negative pressure generating surface so as to continuously extend from near said air inlet end to said air outlet end, said grooves being spaced from each other in the transverse direction of said head slider, said grooves extending along air streamlines generated on said negative pressure generating surface in a CSS zone.
 6. A negative pressure type head slider according to claim 5, wherein said grooves are treated with water repellent. 